Potentiometer insulating device



Jan. 17, 1961 K. E. GooDE ET AL POTENTIOMETER INSULATING DEvcE Filed June 30, 1959 United States Patent() POTENTIOMETER INSULATING DEVICE Kenneth E. Goode and Robert P. Lannerd, Indianapolis, and David P. Zimmerman, Cicero, Ind., assignors to the United States of America as represented by the Secretary of the Navy Filed June 30, 1959, Ser. No. 824,158

8 Claims. (Cl. 3338-166) (Granted under Title 35, U.S. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

The present invention relates to an insulating device for a potentiometer, and more particularly to a device that provides electrical insulation for a variable resistor being used at extremly high voltages and altitudes.

Present day aircraft tire control equipment, such as computers and radars, are presently being designed to operate at eXtreme-ly high voltages, for example up to 35,000 volts, and this equipment is often used at very high altitudes, for example, up to 50,000 feet. The use of high voltage requires special insulating material and devices, not only for insuring satisfactory operation of the equipment, but also in order to make the equipment safe so that it can be operated by personnel without danger of electrocution.

Heretofore, no satisfactory device has been available for adequately insulating a variable resistor, and these u-nits have been a constant hazard, as it is necessary for personnel to make frequent adjustments thereon. The problem is aggravated at high altitudes as the air is less dense and the corona effect is intensified. Thus, danger of sparking becomes very great.

The present invention provides a novel device for mounting and insulating variable resistors by providing an insulator body that is threaded onto a variable resistor and having an insulator shaft provided within the body. A seal is provided between the shaft and the insulator body to serve as a Huid seal and as a locking device for the shaft.

It is, therefore, a general object of the present invention to provide an improved mounting and insulating device for a variable resistor.

Another object of the present invention is to provide an insulating device for a variable resistor that is to be mounted in uid.

Still another object of the present invention is to provide an insulating device having locking means to lock the shaft of a variable resistor.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawing wherein:

Fig. l is a front plan view of a preferred embodiment of the present invention, having the cover removed;

Fig. 2 is a sectional view taken through the longitudinal axis of a preferred embodiment of the present invention; and

Fig. 3 is an oblique View of a Wrench for use with the present invention.

Referring now to the drawing, there is show-n in Fig. 2, a preferred embodiment of the present invention mounted to the front panel 11 of a container having fluid 12, such as oil, therein. A variable resistor 13 is mounted to the front panel 11 by ymeans of an insulator body 14 of insulating material, such as nylon. The insulator body 14 is inserted through a hole 15 in the front panel 11 and is engaged on one end with the threaded portion 16 of the variable resistor 13. The insulator body 14 is secured to the front panel 11 by means of shoulder 17 and nut 18. An O ring 19 of resilient material is provided in order to make a fluid-tight seal.

A shaft 21 of insulating material, such as nylon, is journaled within the insulator body 14 and is provided with a tang 22 that engages the screwdriver slot of the variable resistor shaft 23. The end opposite the tang end of shaft 21 is threaded, and is also provided with a screwdriver slot 24. Nut 25 is threadedly engaged on shaft 21 and a seal 26 of resilient material is positioned around shaft 21 and between nut 25 and the tapered surface 27 on the insulator body 14. Seal 26 serves a dual purpose, for upon tightening of nut 25, seal 26 is compressed against shaft 21 as a result of the tapered surface on the insulator body 14, and serves both as a seal and a locking device.

In operation, variable resistor 13, which is operated at a very high voltage, is attached to the front panel 11 of a container. Locking nut 23 is provided in order to prevent the resistor 13 from turning. When it is desired to adjust the resistance of the variable resistor 13, cover 29 is removed and nut 25 is loosened. To facilitate the loosening of nut 25, slots 31 are provided therein, as best seen in Fig. 1 of the drawing, and a wrench 32, having tabs 33, is engaged with slots 31. As shown in Fig. 3 of the drawing, wrench 32 is provided with a hole 34, and the end of a screwdriver can be passed therethrough to engage slot 24 in shaft Z1. The rotation of shaft 21 in turn causes shaft 23 of the variable resistor- 13 to be turned, and the resistance is changed. Nut 25 is then tightened, while preventing shaft 21 from turning by holding it with a screwdriver. Tightening of nut 25 compresses seal 26, and the tapered surface 27 on insulator body 14 causes seal 26 to bear against shaft 21 to lock this shaft from rotation. Seal 26 also prevents iluid 12 from seeping out.

It can thus be seen that the present invention provides a novel device for mounting a variable resistor, and that the resistor is adequately insulated so that it will not be a hazard when operated at high voltage. It can also be seen that the device is provided with novel locking and sealing means that permit rapid adjustment of the variable resistor.

Obviously many modifications and variations of the present invention are possi-ble in the light of the above teachings. It is, therefore, to be understood that the invention may be practiced otherwise than as specifically described.

What is claimed is:

l. A device for mounting a variable resistor comprising: an insulator body having internal threads on one end for attaching to a shaft-type variable resistor and external threads on the opposite end for attaching to an external structure, said insulator body having a tapered surface on the inner periphery thereof, a shaft of insulating material journaled within said insulator body and havi-ng means for engaging a shaft on said variable resistor, a seal of resilient material on said shaft of insulating material and in engagement with said tapered surface on the inner periphery of said insulator body, and means for compressing said seal against said tapered surface whereby said seal provides a lock and uid seal between said shaft of insulating material and said insulator body.

2. A device for mounting a variable resistor as set forth in claim 1 wherein said means for compressing said seal comprises a nut threadedly attached to said shaft of insulating material.

3. A potentiometer assembly comprising: a container having uid therein, a shaft-type potentiometer, an insulator body for attaching said shaft-type potentiometer to the inside of said container, a shaft of insulating material journaled within said insulator body and having means for engaging a shaft on said potentiometer, a seal of resilient material on said shaft of insulating material, and means for compressing said seal whereby said seal provides a lock and fluid seal between said shaft of insulating material and said insulator body.

4. A potentiometer assembly as set forth in claim 3 wherein said means for compressing said seal comprises a nut threadedly attached to said shaft of insulating material.

5. A potentiometer assembly as set forth in claim 3 wherein said insulator body is threadedly attached to said potentiometer.

6. A potentiometer assembly comprising: a container having fluid therein, a shaft-type potentiometer, an insulator body having one end threadedly attached to said potentiometer and the opposite end attached to said container, said insulator body having a tapered surface on the inner periphery thereof, a shaft of insulating material journaled within said insulator body and having means for engaging a shaft on said potentiometer, a seal of resilient material on said shaft of insulating material and in engagement with said tapered surface on the inner periphery of said insulator body, and means for coml pressing said seal against said tapered surface whereby said seal provides a lock and a fluid seal between said shaft of insulating material and said insulator body.

7. A potentiometer assembly as set forth in claim 6 wherein said means for engaging a shaft on said potentiometer comprises a tang on said shaft of insulating material that is engageable with a screwdriver slot in said shaft on said potentiometer.

8. A device for mounting a variable resistor comprising: an insulator body having means on one end for attaching to a shaft-type variable resistor and means on the opposite end for attaching to an external structure, a shaft of linsulating material journaled within said insulator body and having means for engaging a shaft on said variable resistor, a seal of resilient material on said shaft of insulating material, and a nut threadedly attached to said shaft of insulating material for compressing said seal whereby said seal provides a lock and uid seal between said shaft of insulating material and said insulator body.

References Cited in the tile of this patent UNITED STATES PATENTS 1,950,341 Foothorap Mar. 6, 1934 2,857,496 Louis Oct. 21, 1958 2,871,325 Arisman et al. Jan. 27, 1959 

